1. Field of the Invention
The present invention relates to a machine for smoking at least one cigarette or similar article under given conditions for analyzing the way in which said cigarette is smoked.
Such a machine is used in the tobacco industry for smoking cigarettes, cigarillos or cigars, for determining certain parameters characterizing the quality of the article to be smoked.
There exist two ways of smoking a cigarette for the tester, the first in which the cigarette is consumed freely and the second in which it is subjected to sucking in. The machine of which it is a question here smokes a cigarette according to the second.
2. Description of the Prior Art
Machines of this type are already known which use a suction piston which draws in, in one or more puffs, a constant volume of smoke laden air so as to determine the nicotine and tar content.
In such a machine, the exact flowrate and pressure conditions to which the cigarette is subjected are not known, which makes subsequent comparisons between different cigarettes difficult, other than those relative to the nicotine and tar content. In addition such machines are relatively slow because of their discontinuous operation.
A machine of the above defined type is already known from the U.S. Pat. No. 4,019,366. This machine smokes several cigarettes simultaneously, subjecting each cigarette to a succession of puffs at a given rate. For this, it is provided with adjustment members, for adjusting separately for each of the cigarettes, the air flow which passes through it at each puff, as well as the duration of this puff and the time interval between two successive puffs. In this apparatus, relatively long and complex to use, account is not taken of the variations of behavior of each cigarette during its combustion, which variations may affect the value of the flowrate and cause it to deviate from the a priori adjusted value. In addition, in this apparatus, controlling the conditions to which the cigarettes are subjected uses a flow measurement device, or flowmeter, which is likely to clog up because it comprises very fine calibrated ducts through which the smoke laden air passes.
Furthermore, it is proposed in the French application 89 19432 to use the apparatus for measuring the flowrate-pressure characteristics which it describes for maintaining the flowrate permanently equal to a reference value. This apparatus, which uses a valve controlled by an electronic circuit in response to the instantaneous value of the flowrate, measured by a flowmeter, partially overcomes the preceding drawbacks, but the problem related to clogging up of the flowmeter still exists. In addition, a transformation of the apparatus into a "multi-channel" type apparatus, i.e. allowing several cigarettes to be tested simultaneously, means that as many flowmeters, controllable valves and valve control circuits must be provided as there are channels, which makes the apparatus relatively costly and bulky.